Free flame burners for fuel oils such as gas oil, light fuel oil and the like are distinguishable from each other by their fuel atomisation system.
The fuel atomisation is known to strongly influence the efficiency of the entire system. In this respect, better atomisation leads to better fuel utilisation, lesser soiling of the heat exchangers and lesser pollutant emission into the stack.
For this purpose, the most usual method is to provide mechanical atomisation by feeding the fuel to the atomiser nozzle under high pressure of up to some tens of an atmosphere.
Other systems employing steam, compressed air or water emulsified with the fuel are used, and these are of higher efficiency than mechanical atomisation.
However, such systems have drawbacks when in use, as they require the production of steam, the presence of an air compressor or complicated metering and water emulsifying equipment. Moreover, these systems imply additional water evaporation costs which in some cases strongly penalise the plant energy yield, and they often require frequent and costly maintenance.
For many types of fuel oil of high viscosity, density and evaporation temperature, it is also necessary to use a preheater before feeding the oil to the nozzle, with additional plant costs.
The object of the present invention is therefore to provide a burner which obviates the aforesaid problems by providing high-efficiency atomisation even with oils having characteristics at the limits of the official specifications, the fuel being heated to the necessary level for optimum atomisation without additional energy and plant costs.